Electromagnetically operated fuel injection valve

ABSTRACT

An electromagnetically operated fuel injection valve wherein the orifice of the injection nozzle discharges fuel into an atomizing chamber having an outlet which is co-axial with the orifice and is in direct communication with the intake manifold of an internal combustion engine. The chamber is defined by a cylindrical inner sleeve having one or more tangential openings for admission of air which atomizes the fuel in the chamber prior to entry into the manifold. The quantity of air admitted by way of the opening or openings amounts to between one-third and onehalf of the quantity required by the engine during idling. The inner sleeve is surrounded by an outer sleeve which defines therewith an air-filled compartment in communication with the opening or openings of the inner sleeve.

United States Patent Romann et a1.

[ 1 Aug. 1,1972

[54} ELECTROMAGNETICALLY OPERATEDFUEL INJECTION VALVE Robert Bosch GmbH, Stuttgart, Germany Filed: July 26, 1971 Appl. No.: 166,211

[73] Assignee:

[30] Foreign Application Priority Data [51] Int. Cl. ..B05b 1/30 [58] Field of Search ..239/583, 584,585

References Cited UNITED STATES PATENTS 1/1918 Fisher ..239/584 4/1928 French ..239/585 FOREIGN PATENTS OR APPLICATIONS 1,282,158 12/1961 France ..239/585 150,638 7/1955 Sweden ..239/585 Primary Examiner-M. Henson Wood, Jr.

' Assistant Examiner-Edwin D. Grant Attorney-Michael S. Striker [5 7] ABSTRACT An electromagnetically operated fuel injection valve wherein the orifice of the injection nozzle discharges fuel into an atomizing chamber having an outlet which is co-axial with the orifice and is in direct communication with the intake manifold of an internal combustion engine. The chamber is defined by a cylindrical inner sleeve having one or more tangential openings for admission of air which atomizes the fuel in the chamber prior to entry into the manifold. The quantity of air admitted by way of the opening or openings amounts to between one-third and one-half of the quantity required by the engine during idling. The inner sleeve is surrounded by an outer sleeve which defines therewith an air-filled compartment in communication with the opening or openings of the inner sleeve.

10 Claims, 2 Drawing Figures dandy/1.11111:

PATENTEDAUB I 1972 3 6 80, 7 94 Fig. 7

26 27 Iii 32 28 INVENTORS Peter ROMANN Heinrich KNAPF Paul FUSSNER their ATTORNEY BACKGROUND OF THE INVENTION The present invention relates to improvements in electromagnetically operated fuel injection valves for use in internal combustion engines, and more particularly to improvements in valves which are designed to inject metered quantities of atomized fuel into the intake manifolds or suction manifolds of internal combustion engines. Still more particularly, the invention relates to improvements in fuel injection valves serving toinject fuel which is maintained at a relatively low pressure into the intake manifold of an internal combustion engine in such a way that the length of intervals during which the valve remains open determines the quantity of atomized fuel which is admitted into the intake manifold.

The presently known fuel injection valves which serve to admit atomized fuel into the intake manifold of 20 an internal combustion engine normally comprise a valve member which is reciprocable by a spring and by an electromagnet in such a way that the spring tends to maintain the valve member in its closed or sealing position but yields in response to energization of the electromagnet toadmit into the intake manifold fuel in such quantities as are determined by the length of the interval during which the electromagnet remains energized. The valve member is secured to a reciprocable armature of the electromagnet which further comprises I a fixed soft iron core and a winding surrounding the core. A portion of the valve body normally consists of soft iron to define a portion of the closed path for magnetic force lines when the electromagnet is energized.

As a rule, the length of intervals of injection of fuel into the manifold is extremely short, normally in the range of one or more milliseconds. Each energization of the electromagnet entails a movement of the valve member to its opening position in that a portion of the valve member is lifted off a seat in the nozzle of the valve body whereby the orifice of the nozzle discharges a stream of fuel into the intake manifold. The length of intervals of fuel injection is preferably controlled by electrical or electronic control means so as to be a function of several factors which are indicative of the momentary operating condition and requirements of the internal combustion engine.

It was found that the quantity of deleterious combustion products is reduced if the fuel enters the intake manifold in finely atomized condition. Thus, satisfactory atomization of injected fuel will result in a substantial reduction of the quantity of undesirable combustion products.

SUMMARY OF THE INVENTION An object of the invention is to provide a novel and improved valve for injection of fuel into the intake manifold or suction manifold of an internal combustion engine and to provide such valve with novel and improved means for enhancing the atomization of fuel prior to entry into the intake manifold.

Another object of the invention is to provide a fuel injection valve with simple, compact and reliable means for effecting a fine atomization of fuel which is being discharged by the orifice of the nozzle and is about to enter the intake manifold of the internal combustion engine.

A further object of the invention is to reduce the quantity of undesirable combustion products in internal combustion engines with manifold injection of atomized fuel.

An additional object of the invention is to provide a device for atomizing fuel which issues from the orifice of the nozzle in a valve for injection of atomized fuel into the intake manifold of an internal combustion engme.

The invention is embodied in an electromagnetically operated valve for injection of atomized fuel into the intake manifold of an internal combustion engine. The valve comprises a body including a nozzle which is provided with a fuel-discharging orifice, a valve member having a portion which is movable with reference to the orifice between an opening position and a sealing position, means for biasing the valve member and its portion to the sealing position, an electromagnet which is energizable to move the valve member and its portion to the opening position against the opposition of the biasing means whereby the orifice of the nozzle discharges a predetermined quantity of fuel which undergoes at least some atomization while leaving the interior of the nozzle, an enclosure connected with the valve body and defining an atomizing chamber which is outwardly adjacent to the orifice to receive a predetermined quantity of preferably partly atomized fuel in response to movement of the valve member and its por- 0 tion to the opening position, an outlet provided in the enclosure for evacuation of atomized fluid and being in at least substantial axial alignment with and spaced from the orifice of the nozzle, one or more openings provided in the enclosure to supply to the chamber currents of air which atomizes the fuel entering the chamber by way of the orifice of the nozzle, such opening or openings being radially spaced from the orifice and extending substantially at right angles to the axis of the nozzle, and means for supplying to the opening or openings currents of air whichflows substantially tangentially along the internal surface of the enclosure and effects a further atomization of partly atomized fuel which enters the chamber in response to movement of the valve member and its portion to the opening position. The finely atomized fuel leaves the chamber by way of the outlet in the enclosure and is admitted into the intake manifold of the internal combustion engine.

When the pressure of air in the intake manifold drops, the manifold draws air into the chamber by way of the opening or openings in the enclosure and such air effects a highly satisfactory atomization of fuel which is being admitted by way of the orifice in the nozzle of the fuel injection valve.

The novel features which are considered as characteristic of the invention are set forth in Particular in the appended claims. The improved fuel injection valve itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an axial sectional view of a fuel injection valve which embodies the invention, further showing a portion of the intake manifold; and

FIG. 2 is a transverse sectional view as seen in the direction of arrows from the line IIII of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawing illustrates an electromagnetically operated fuel injection valve which serves to admit sprays of finely atomized fuel into the intake manifold 40 of an internal combustion engine. The valve comprises a housing or body including a main portion 1 which consists of steel and has a central axial bore 2 receiving a spool-shaped plastic frame 3 for the winding 4 of an electromagnet. The lower end of the bore 2 communicates with a coaxial smaller-diameter bore 5 for the armature 12 of the electromagnet. The soft-iron core 6 of the electromagnet is surrounded by and extends upwardly beyond the frame 3 and beyond the main portion 1 of the valve body. The core 6 is coaxial with the armature 12 and serves as a means for admitting fuel to the axial passage 16 (shown by broken lines) of a reciprocable valve member 13 which is threadedly connected with the armature 12 and extends downwardly into a nozzle which is sealingly received in the lower part of the main body portion 1 and is held therein by a bent-over flange 14 of the portion 1. The upper end portion 7 of the soft iron core 6 extends beyond the body portion 1 and is sealingly connected with the discharge end of a fuel supplying conduit 8. A ring 9 on the core 6 is fixedly held in the main body portion 1 by a bent-over flange 10; this ring serves to guide the magnetic force lines from the core 6 into the main body portion 1. The armature 12 is adjacent to the inner or lower end portion of the soft iron core 6. The axial passage 16 of the valve member 13 communicates with a diametrically extending passage 17 which discharges fuel radially into the interior of the nozzle 15. Such fuel flows along peripheral flats 18 provided on an enlarged portion 13b of the valve member 13 and accumulates in a space 19 which is immediately adjacent to a fuel discharging orifice 21 provided in the end wall 20 of the nozzle 15. The inner end of the orifice 21 is surrounded by a seat 22 for a conical sealing portion 13a of the valve member 13. The latter further comprises an end portion or pin 20 which is normally received in the orifice 21 to prevent the escape of fuel from the space 19. The pin 20 is received in the orifice 21 with small radial clearance and is movable by the electromagnet including the armature 12 from the illustrated sealing position to a retracted or opening position to thereby admit a metered quantity of fuel from the space 19 into an atomizing chamber 26 which is immediately adjacent to the outer or discharge end of the orifice 21. When the pin 20 is held by the electromagnet in the illustrated sealing position, the aforementioned conical portion 13a of the valve member 13 is in sealing engagement with the seat 22 of the nozzle 15. The conical portion 13a of the valve member 13 is located between the enlarged portion 13b and the pin 20.

When a current of requisite strength is caused to flow through the winding 4 of the electromagnet in the main body portion 1, the armature 12 moves axially and away from the nozzle 15 against the opposition of a helical spring 24 which reacts against an internal shoulder in the soft-iron core 6 and normally urges the valve member 13 to its sealing position. Energization of the winding 4 results in movement of the conical portion 13a away from the seat 22 so that a predetermined quantity of pressurized fuel can leave the space 19 in the nozzle 15 and flows through the orifice 21 to enter the atomizing chamber 26. The fuel in the space 19 is assumed to be maintained at a pressure of two atmospheres above atmospheric pressure. If the pressure of fuel is substantially constant, the length of the interval of energization of the winding 4 determines the quantity of fuel which enters the atomizing chamber 26 in response to movement of the pin 20 on the valve member 13 to its opening position. The lifted pin 20 defines with the end wall of the nozzle 15 an annular duct for the flow of pressurized fuel into the atomizing chamber 26. The fuel which enters the chamber 26 is being atomized at the annular edge on the lower end of the pin 20.

The atomization of fuel in the chamber 26 is enhanced by currents of air admitted into the chamber 26 at one or more points which are radially spaced from the axis of the orifice 21. In the illustrated embodiment, the chamber 26 is defined by an inner enclosure or sleeve 27 which is sealingly secured to and surrounds a portion of the nozzle 15. The bottom end wall of the inner sleeve 27 has an outlet 33 which discharges finely atomized fuel directly into the intake manifold 40 of the internal combustion engine. The cylindrical wall 28 of the inner sleeve 27 has a preferably cylindrical internal surface which is coaxial with the orifice 21 and outlet 33 and is provided with one or more tangential air-admitting openings. As shown in FIG. 2, the cylindrical wall 28 has two openings 30, 31 which are disposed diametrically with reference to each other and discharge currents of air substantially tangentially of the internal surface of the sleeve 27. If desired, the wall 28 can be provided with a single opening or with three or more preferably equidistant openings for admission of atomizing air. The outlet 33 is provided in the end wall 32 of the inner sleeve 27 and this end wall is surrounded by a ring-shaped inwardly extending collar on an outer enclosure or sleeve 37 which defines with the sleeve 27 an annular air-filled compartment 35. The latter receives air from a supply pipe 39 which is brazed to the outer sleeve 37, as at 38. The diameter of the outlet 33 is substantially smaller than the internal diameter of the cylindrical wall 28, i.e., substantially smaller than the diameter of the atomizing chamber 26 The outer sleeve 37 sealingly surrounds and is secured to a cylindrical part 36 of the main body portion 1. The supply pipe 39 receives air from the air funnel (not shown) of the internal combustion engine. The intake manifold 40 sucks air from the compartment 35 by way of the openings 30, 31 and outlet 33 of the inner sleeve 27.

The diameters of the openings 30, 31 in the inner sleeve 27 are selected in such a way that these openings constitute effective restrictors for the inflow of air into the manifold 40 by way of the outlet 33. In order to allow for a sufficiently wide range of adjustments when the engine including the intake manifold 40 is idling, the cross-sectional areas of the openings 30, 31 are dimensioned in such a way that these openings admit only a fraction of the air which is required by the engine during idling, preferably between one-third and one-half of the air which is needed during such operation of the engine. It is clear, however, that the throttling of air flow into the intake manifold 40 by way of the outlet 33 of the inner sleeve 27 can be effected by one or more flow restrictors which are provided in another part of the valve, for example, in the supply pipe 39.

It was found that the fuel which is admitted into the atomizing chamber 26 of the inner sleeve 27 undergoes particularly intensive atomization if the sleeve 27 is provided with twoor more equidistant airadmitting openings. The openings 30, 31 can but need not be located in a common plane which is normal to the axis of the nozzle 15. Also, the axes of the openings 30, 31 can be located in planes which are inclined with reference to a plane that is normal to the axis of the nozzle 15. v

Satisfactory atomization of fuel which enters the intake manifold 40 is especially important when the engine is idling and also when the engine is operated at partial load. The aforediscussed dimensioning of openings 30, 31 so that they admit only a fraction of the total quantity of air which is needed for the operation of the engine during idling is desirable in order to insure that the idling operation of the engine can be regulated within a relatively wide range.

The detailsof the electrical or electronic control system which regulates the timing and the length of intervals of energization of the electromagnet in the main body portion 1 form no part of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended 1. In an electromagnetically operated valve for injection of fuel into the intake manifold of an internal combustion engine, a combination comprising a body including a nozzle having a fuel-discharging orifice; a valve member having a portion movable with reference to said orifice between an opening position and a sealing position; means for biasing said portion of said valve member to said sealing position; an enclosure connected with said body and defining an atomizing chamber outwardly adjacent to said orifice to receive a predetermined quantity of fuel in response to movement of said portion of said valve member to said opening position, said enclosure having an outlet for atomized fuel positioned in at least substantial axial alignment with and spaced from said orifice and at least outlet comgiunicaes with the intake manifald of the engine so t at San opening admits into sai chamber air in response to a drop in pressure in said manifold 3. A combination as defined in claim 2, wherein said enclosure is provided with a plurality of at least substantially equidistant air-admitting openings each of which is radially spaced from and extends substantially at right angles to the axis of said orifice.

4. A combination as defined in claim 2, wherein the cross-sectional area of said opening is such that the quantity of air admitted by way of said opening is a fraction of the quantity required by the engine during idling.

5. A combination as defined in claim 4, wherein the quantity of air admitted by way of said opening is between one-third and one-half of the quantity required by the engine during idling.

6. A combination as defined in claim 1, wherein said enclosure has a substantially cylindrical internal surface and said opening is substantially tangential to said internal surface.

7. A combination as defined in claim 6, wherein said internal surface is coaxial with said orifice and said outlet.

8. A combination as defined in claim 1, wherein said air supplying means comprises a second enclosure surrounding said first mentioned enclosure and defining therewith an air-filled compartment communicating with said opening.

9. A combination as defined in claim 1, wherein said enclosure extends directly into an opening of the intake manifold in the engine so that atomized fuel leaving said outlet enters the interior of such manifold.

10. A combination as defined in claim 1, wherein said biasing means comprises a spring bearing against said valve member and reacting against said body, and further comprising electromagnet means provided in said body and energizable to move said portion to said opening position against the action of said spring. 

1. In an electromagnetically operated valve for injection of fuel into the intake manifold of an internal combustion engine, a combination comprising a body including a nozzle having a fueldischarging orifice; a valve member having a portion movable with reference to said orifice between an opening position and a sealing position; means for biasing said portion of said valve member to said sealing position; an enclosure connected with said body and defining an atomizing chamber outwardly adjacent to said orifice to receive a predetermined quantity of fuel in response to movement of said portion of said valve member to said opening position, said enclosure having an outlet for atomized fuel positioned in at least substantial axial alignment with and spaced from said orifice and at least one air-admitting opening extending substantially at right angles to the axis of and radially spaced from said orifice; and means for supplying to said opening a current of air to atomize the fuel which is admitted into said chamber by way of said orifice before the thus atomized fuel leaves said chamber by way of said outlet.
 2. A combination as defined in claim 1, wherein said outlet communicates with the intake manifold of the engine so that said opening admits into said chamber air in response to a drop in pressure in said manifold.
 3. A combination as defined in claim 2, wherein said enclosure is provided with a plurality of at least substantially equidistant air-admitting openings each of which is radially spaced from and extends substantially at right angles to the axis of said orifice.
 4. A combination as defined in claim 2, wherein the cross-sectional area of said opening is such that the quantity of air admitted by way of said opening is a fraction of the quantity required by the engine during idling.
 5. A combination as defined in claim 4, wherein the quantity of air admitted by way of said opening is between one-third and one-half of the quantity required by the engine during idling.
 6. A combination as defined in claim 1, wherein said enclosure has a substantially cylindrical internal surface and said opening is substantially tangential to said internal surface.
 7. A combination as defined in claim 6, wherein said internal surface is coaxial with said orifice and said outlet.
 8. A combination as defined in claim 1, wherein said air supplying means comprises a second enclosure surrounding said first mentioned enclosure and defining therewith an air-filled compartment communicating with said opening.
 9. A combination as defined in claim 1, wherein said enclosure extends directly into an opening of the intake manifold in the engine so that atomized fuel leaving said outlet enters the interior of such manifold.
 10. A combination as defined in claim 1, wherein said biasing means comprises a spring bearing against said valve member and reacting against said body, and further comprising electromagnet means provided in said body and energizable to move said portion to said opening position against the action of said spring. 